Method of producing composite bushings and bearings

ABSTRACT

Bearings may be formed by a composite material consisting of a sheet of steel lined with a bearing material. The lining process is performed by rotating a steel cylinder internally lined with a bearing metal, applying pressure by means of a roll of relatively small diameter upon the outer surface and applying pressure by means of a roll of relatively large diameter upon the inner surface of the cylinder while rotating the same, and cutting the cylinder open upon completion of the rolling process.

United States Patent [1 1 Timmermans METHOD OF PRODUCING COMPOSITEBUSHINGS AND BEARINGS [76] Inventor: Franz D. Timmermans, BrunswikerStr. 11 a, 23 Kiel, Germany Notice: The portionof the term of thispatent subsequent to Oct. 14, 1991, has been disclaimed.

[22] Filed: Jan. 29, 1970 [21] Appl. No.: 9,135

[52] U.S. Cl 72/68, 72/80, 72/700, 29/ 149.5 S [51] Int. Cl B2lb 3/00[58] Field of Search 29/DIG. 6, 149.5 S, 527.7, 29/l48.4 R, 149.5 R,149.5 C; 72/68, 69, 110, 80, 700

' [56] References Cited UNITED STATES PATENTS 1,072,436 9/1913 Dicks29/1604 1*Jan. 14, 1975 1,920,022 7/1933 Six ..'29/149.5 3,653,1094/1972 Timmermans 29/1495 FOREIGN PATENTS OR APPLICATIONS 110,433 0/1964Czechoslovakia 29/1495 Primary Examiner-Lowell A. Larson Attorney,Agent, or Firm-Erwin Salzer [57] ABSTRACT Bearings may be formed by acomposite material consisting ofa sheet of steel lined with a bearingmaterial.

The lining process is performed 'by rotating a steel cylinder internallylined with a bearing metal, applying pressure by means of a roll ofrelatively small diameter upon the outer surface and applying pressureby means of a roll of relatively large diameter upon the inner surfaceof the cylinder while rotating the same, and cutting the cylinder openupon completion of the rolling process.

2 Claims, 1 Drawing Figure METHOD OF PRODUCING COMPOSITE BUSHINGS ANDBEARINGS BACKGROUND OF THE INVENTION 7 When a steel cylinder which hasbeen internally lined by centrifugal action with a bearing metal, e.g.,with lead bronze, is subsequently cut open (e.g., along the weldinitially established to form a steel cylinder out of a sheet of steel),the slotted steel cylinder must be flattened and rolled between rolls inorder to obtain a material that lends itself to the formation ofbearings. The aforementioned rolling process is a source of considerabledifficulties because the layer of bearing metal spreads more under theaction of pressure rolls than the layer of steel. As a result of thefact that the spreadingout of the layer of bearing metal under theaction of pressure rolls by far exceeds the spreading-out of the steelbacking of said layer under the action of such rolls, one obtains abearing metal steel composite that is curved rather than planar. It isthe principal object of this invention to provide a rolling process forbearing metal'and steel laminates which eliminates the aforementioneddrawbacks, and results in a product having improved performancecharacteristics.

SUMMARY OF THE INVENTION The rolling process according to this inventionincludes the steps of arranging a steel cylinder which is internallylined with bearing metal within a gap formed by a pair of juxtaposedrolls of which one roll has a relatively small diameter and the otherroll has a relatively large diameter, thereafter applying a relativelylarge caused to rotate by rolls e and a. A'pair of rolls g rotatablymounted on shafts h arranged above cylinder m serve substantially thesame purpose as lower rolls g. All rolls g are provided with flanges ffor positioning cylinder m. The drawing further shows four small rollersi provided to prevent lateral motion of cylinder m. Reference characterm has been applied to indicate the composite steel-lead-bronze cylinderin its final shape upon completion of the rolling application. Thisshape of cylinder m'has been indicated in solid lines. The dotted line mindicates the shape of the steel-leacl-bronze cylinder m before therolling process is intiated. When the steel-lead-bronze cylinder massumes the shape indicated in solid lines the same is removed from therolling machine, cut or sliced in axial direction, and the spread out orflattened to form a planar lead-bronze lined sheet of steel. Thismaterial may then be formed upon rolling thereof, and causing said steelcylinder to assume a planar shape after having been cut open.

BRIEF DESCRIPTION OF THE DRAWING The drawing is an end view of a rollersystem for carrying this invention into effect and shows some of theconstituent parts of the system sectionalized trasversely.

DESCRIPTION OF PREFERRED METHOD In the drawing reference character m hasbeen applied to indicate a cylinder of steel which is internally linedwith lead bronze. Reference character e has been applied to indicate aroll having a relatively large diameter supported by, and rotatablyaround, the axis 11. The

into bearings of bushings, as is well known in the art. The compositelead-bronze lined steel sheets obtained by the above described rollingprocess are characterized by a fine or dense metallurgical bond betweenthe two layers of which the laminate is formed.

Another important advantage of the process according to this inventionresides in the fact that it lends itself very well to automation. Incase of automation the large diameter inner roll e ought to besubdivided into two roll sections which may be separated by relativemovement inaxial directions. This feature facilitates placement ofcomposite cylinder m on roll e. The admission to and removal from theroll e of cylinder m is preferably effected by means of electromagnets.Loading of roll e with steel cylinders m involves a temporary removal ofupper rolls a,g from roll e. The slicing of cylinders m along ageneratrix thereof and the flattening of the sliced steel cylinders iseffected by another machine, not shown.

It will be understood that in the basic structure illustrated thespecific pressure exerted by roll a on the steel backing of cylinder mis larger than the specific pressure exerted by roll e on theload-bronze lining of cylinder m on account of the factthat the diameterof roll a is less than that of roll 2. The difference in pressureexerted by rolls a,e compensates in part for the tendency of the lininglayer n to spread, or extend, more than the steel layer. The surplus orexcess of spreading out or extension of the lining layer over that ofthe steel backing layer results in subjecting the latter to stresseswhich are re-inforced by centrifugal forces acting upon the lininglayer. These stresses have the tendency to flatten the steel backinglayer of cylinder m. The magnitude of these stresses depends upon thenumber of revolutions at which cylinder m is rotated.

The number of revolutions of cylinder m when being rolled may becontrolled in such a fashion that cylinder m extends into asubstantially flat sheet upon being cut open.

I claim as my invention:

1. A method of rolling steel cylinders which are internally lined with abearing metal including the steps of arranging a steel cylinderinternally lined with a bearing metal within a gap formed by a pair ofjuxtaposed rolls of which one roll has a relatively small diameter andthe other roll has a relatively large diameter, thereafter applying arelatively large pressure by said roll of relatively small diameteragainst the outer surface of said steel cylinder and of applying arelatively small pressure by said roll of relatively large diameteragainst said inner bearing-metal-lined surface of said steel cylinderand causing said pair of rolls to rotate while applying pressure againstsaid outer surface and against said inner surfaceof said steel cylinder,cutting said steel cylinder open upon rolling thereof, and causing said5 steel cylinder to assume a planar shape after having been cut open.

2. A process as specified in claim 1 wherein the numcutopen.

1. A method of rolling steel cylinders which are internally lined with abearing metal including the steps of arranging a steel cylinderinternally lined with a bearing metal within a gap formed by a pair ofjuxtaposed rolls of which one roll has a relatively small diameter andthe other roll has a relatively large diameter, thereafter applying arelatively large pressure by said roll of relatively small diameteragainst the outer surface of said steel cylinder and of applying arelatively small pressure by said roLl of relatively large diameteragainst said inner bearing-metal-lined surface of said steel cylinderand causing said pair of rolls to rotate while applying pressure againstsaid outer surface and against said inner surface of said steelcylinder, cutting said steel cylinder open upon rolling thereof, andcausing said steel cylinder to assume a planar shape after having beencut open.
 2. A process as specified in claim 1 wherein the number ofrevolution of said steel cylinder when being rolled is controlled insuch a fashion that said steel cylinder extends into a substantiallyflat sheet upon being cut open.